Vibration at low end torque

Many times a balance issue will go away at higher speeds Even a bent driveshaft or rim. A Loose wheel can run along balanced out, tilllugs break. Maybe a balance issue that balances out with increased speed/ RPMs. Big maybe.

 

my transmission tail shaft has a little play, barely noticable when under torque.

 

Did you match mark your u joints when taking apart?

 

One of our guys is having similar problem with a 2018 Mack mDrive.
How ever it starts the morning out fine, smooth as glass.
Within 20 minutes the vibration appears.
Especially bad around sixth gear, 20 mph. Empty is vibrates, loaded it vibrates really bad under higher torque.
He is suspecting the air suspension, but the dealer has changed the valve four times. Wondering if there is a restriction in the air lines to the air bags, letting the air in but not out as fast.
When he stops, the air suspension dumps air for many minutes before leveling out.

 

Oh no, I just realized, I didn’t mark mine. Putting in tomorrow, hopefully. Oh well 50/50 chance. I guess.

 

Could be ride height too maybe axle torque arm

 

What suspension system do you have? Did you have spacer plates between hanger bearing and mount?